最大化小维数图的补的谱半径的统一方法

在树、单圈图、双圈图和三圈图的补图中,本文给出了统一的方法来刻画具有极大谱半径的图.     

海岸和近海工程国家重点实验室近期研究工作简介

1 实验室概况 大连理工大学海岸和近海工程国家重点实验室1986年由国家计委批准筹建,1990年通过国家验收后被批准正式对国内外开放.1994年、1997年和2003年3次通过了国家计委/科技部委托国家自然科学基金委组织的评估.     

N维纯时滞微分方程的稳定性

本文考虑了n维纯时滞微分方程的稳定性,利用分析技巧给出纯时滞微分方程稳定的几个充分条件.当n=1时,所得结论推广和改进了Yorke等人的相应结论.     

局部强组态相互作用及其对ClⅨ—CaⅫ离子2P~44f组态能级结构的影响

利用包括相对论效应的组态相互作用理论方法，详细研究了类氟等电子系列ＣｌⅨ－ＣａⅫ离子的奇宇称激发态结构，讨论了存在于这些离子上的局部强组态相互作用及其对２Ｐ４４ｆ组态能级结构的影响，具体给出了包括强组态相互作用效应修正的能级的计算结果。     

On the well‐posedness for Keller–Segel system with fractional diffusion

In this paper, we study the Cauchy problem for the Keller–Segel system with fractional diffusion generalizing the Keller–Segel model of chemotaxis for the initial data (u₀,v₀) in critical Fourier‐Herz spaces with q ∈ [2, ∞], where 1 < α ≤ 2. Making use of some estimates of the linear dissipative equation in the frame of mixed time‐space spaces, the Chemin ‘mono‐norm method’, the Fourier localization technique and the Littlewood–Paley theory, we get a local well‐posedness result and a global well‐posedness result with a small initial data. In addition, ill‐posedness for ‘doubly parabolic’ models is also studied. Copyright © 2011 John Wiley & Sons, Ltd.     

Structural identification of mouse fecal metabolites of theaflavin 3,3'-digallate using liquid chromatography tandem mass spectrometry

Black tea consumption has been associated with many health benefits including the prevention of cancer and heart disease. Theaflavins are the major bioactive polyphenols present in black tea. Unfortunately, limited information is available on their biotransformation. In the present study, we investigated the metabolic fate of theaflavin 3,3'-digallate (TFDG), one of the most abundant and bioactive theaflavins, in mouse fecal samples using liquid chromatography/electrospray ionization tandem mass spectrometry by analyzing the MS(n) (n=1-3) spectra. Four metabolites theaflavin, theaflavin 3-gallate, theaflavin 3'-gallate, and gallic acid were identified as the major mouse fecal metabolites of TFDG. Glucuronidated and sulfated, instead of methylated metabolites of theaflavin 3-gallate, theaflavin 3'-gallate, and TFDG were detected and identified as the minor mouse fecal metabolites of TFDG. Our results indicate that TFDG can be degraded in mice. Further studies on the formation of those metabolites in TFDG-treated mice in germ-free conditions are warranted. To our knowledge, this is the first report on the biotransformation of TFDG in mice.     

A Back Propagation Artificial Neural Network Prediction Model of the Gate Freeze Time for Injection Molded Polypropylenes

This paper presents a back propagation artificial neural network (BP ANN) prediction model of the gate freeze time (t_gf) for injection molded polypropylenes. An orthogonal design method was applied to enhance the BP ANN performance. The test results on the performance of the BP ANN prediction model showed that it can predict t_gf with reasonable accuracy. Utilizing the BP ANN prediction model, the effects of the process factors, melt temperature (T_me), fill time (t_f), gate area (A_in), packing pressure (P_p), and mold temperature (T_mo) on t_gf were investigated. The simulation results showed that the most important process factor affecting t_gf was T_me, followed by t_f, A_in, and P_p, with T_mo having the least effect. The gate freeze time increased with elevated T_me, t_f, A_in, and P_p.     

强激光场中模型氢原子和真实氢原子产生高次谐波的比较

通过数值求解原子在强激光场中的含时薛定谔方程,研究了有库仑奇点和无库仑奇点的一维模型氢原子和三维真实氢原子产生高次谐波的特性.结果表明,有库仑奇点和无库仑奇点的一维模型氢原子和三维真实氢原子产生高次谐波的截止位置相同,但是高次谐波强度变化特征明显不同,进一步的研究表明,无库仑奇点的模型氢原子产生的高次谐波谱相对变化趋势与三维真实氢原子的高次谐波谱变化趋势是完全一致的.     

On asympotic behavior of solutions to several classes of discrete dynamical systems

In this paper, a new complete and simplified proof for the Husainov-Nikiforova Theorem is given. Then this theorem is generalized to the case where the coefficients may have different signs as well as nonlinear systems. By these results, the robust stability and the bound for robustness for high-order interval discrete dynamical systems are studied, which can be applied to designing stable discrete control system as well as stabilizing a given unstable control system.     

希土8-羟基喹啉醋酸盐的合成与性质

希土元素能通过氮、氧等杂原子的配位与许多有机化合物形成配合物。R.G.Charles合成了β-二酮醋酸铕。在这一化合物中,醋酸根是很好的离去基团,它能被许多有机金属负离子(如-Fe(CO)_2C_5H_5,-Sn(C_6H_5)_3)和碳负离子L<二] ,—CH(CH_3)_2)取代生成RE-M键和RE-C键,因而具有相当的研究价值。我们合成了希土8-羟基喹啉醋酸盐,测试了它们的热稳定性、磁性和红外光谱。